The present invention addresses a problem encountered by just about every person at one time or another—the dreaded cold shower. We all know the sequence. A person enters a shower, anticipating that the hot water will last long enough to complete the shower. Unbeknownst to the showerer, another person has been using hot water (or at least more hot water than the showerer thought was being used), depleting the hot water in the water heater tank. After a few minutes in the shower, the water temperature starts to cool. This usually occurs just as one has completed the lather phase of the shampooing process. The showerer adjusts the faucet position(s) to try to maintain an adequate water temperature. This works for a short period of time (unfortunately, not long enough to complete the rinse phase), but soon the hot water temperature is reduced to the point that only cold water flows from the showerhead. This is not a pleasant situation.
There are known solutions to the cold shower problem, but most are not viable. In the context of a single-family household setting, one solution is to become single again, thereby eliminating other hot water consumers. However, this option generally doesn't sit well with spouses and children. Another solution is to yell at the teenagers in the house, who believe a long shower makes up for a short attention span (as pertains to parents). A potentially more realistic solution is to buy a larger hot water tank, or better yet, multiple hot water tanks. As with the other solutions, this usually is not viable, due to space restrictions and other reasons, such as lack of money due to the spending habits of the spouse and/or teenagers and fear of large payments to the local energy utility. Even households with multiple tanks are prone to run out of hot water sooner or later.